Foundations of Atomic Structure - Democritus and Dalton

Even in his own time, John Dalton was a very famous man due to his atomic theory; however, his atomic theory was not the first time that the notion of the atom was proposed. An ancient Greek philosopher named Democritus was the first to consider that matter had a very small indestructible particle. The difference between the theories of the early Greeks and Dalton's theory was that Dalton’s atomic theory was based on experimental evidence and the early Greeks were merely philosophizing about such things. Dalton’s great contribution to the atomic theory led to a modern understanding of the relative size and nature of atoms, as well as how they fit together in definite proportions in a specific compound. He was not always extremely accurate, but his principle has formed the basis of modern chemistry.